The invention is based on a fuel injection apparatus for internal combustion engines, and more particularly for Diesel engines. A fuel injection apparatus of this type is already known (U.S. Pat. No. 3,486,493), in which the injection pump is embodied as a pump/nozzle and the fuel injection quantity is determined by means of a hydraulically driven control slide inserted in an overflow channel. This control slide determines the effective supply stroke and develops the fuel injection quantity of the injection pump by means of blocking the return flow out of the pump work chamber; and the injection is terminated when this control slide opens the overflow channel and the injection pressure can be relieved. In this known fuel injection apparatus, the control device which is common for all the injection pumps comprises a mechanical rotary distributor driven in synchronism with the engine camshaft; this rotary distributor determines both the onset and the end of fuel injection, controls an rpm-dependent variation in supply onset via a control sheath which is mechanically displaceable by flyweights, and simultaneously acts as a distributor device by means of which the control fuel is delivered to the various pressure chambers of the control slide. A control device of this kind, mechanically driven, is greatly dependent on rpm; that is, the injected quantity of fuel varies when the rpm is varying despite an unchanged placement of the adjusting members. This limits its applicability in high-speed engines. A further disadvantage is that the control pressure line also acts as a filling line, so that negative influence retroactively exerted on the control of fuel quantity and controlled times must be expected.
A fuel injection apparatus of virtually the same type is also known from U.S. Pat. No. 3,465,737; however, in this apparatus the control slide is actuated by the control pressure of a separate injection pump, acting as a control pump, which is driven simultaneously with the pump/nozzle. In order to vary the injection onset, a known injection adjuster which transmits the drive torque is built into the driven mechanism of the control pump, so that the total cost for this apparatus is very high.
Fuel injection apparatuses having pump/nozzles controlled by magnetic valves are also known, in which the control slide inserted in the overflow channel is embodied by the valve member of a magnetic valve assembly. In these apparatuses, each pump/nozzle has associated with it a magnetic valve directly exposed to the injection pressure, so that there are unavoidable variations in performance from one example to another, and the pressure forces engaging the valve member, when the pump/nozzles are used in multicylinder engines, prevents the provision of an identical supply quantity for each pump/nozzle.